A U.S. aircraft carrier entered a zone near the Strait of Hormuz where Iran is holding naval drills, an Iranian official said on Thursday amid rising tensions over the key oil passway.

US aircraft carrier USS John C. Stennis [File photo]

"A U.S. aircraft carrier was spotted inside the manoeuvre zone ... by a navy reconnaissance aircraft," Commodore Mahmoud Mousavi, the spokesman for the Iranian exercises, told the official IRNA news agency.

Iranian aircraft recorded video and photos of the U.S. vessel, he said.

Mousavi also said the Iranian navy's aircraft and helicopters continued surveillance and reconnaissance operations during the sixth day of major naval drills to monitor activities of all units in the area of the military exercises.

A U.S. navy spokeswoman refused to comment on the footage but confirmed that aircraft carrier USS John C Stennis was on a "routine transit" through the Strait to provide support to NATO forces in Afghanistan.

"Americans are not in a position whether to allow Iran to close off the Strait of Hormuz,"Salami was quoted as saying by the official IRNA news agency.

"We will not relinquish our strategic moves if Iran's vital interests are undermined by any means," Iranian General Hossein Salami told Press TV.

The Iranian Navy started its10-day massive naval exercises in the international waters last Saturday.

The naval drills, dubbed Velayat 90, cover an area of 2,000 km stretching from the east of the Strait of Hormuz in the Persian Gulf to the Gulf of Aden.

It is the first time the Iranian Navy carries out naval drills in such a vast area, Iran's Navy Commander Rear Admiral Habibollah Sayyari said at a press conference last week.